The invention relates to a telecommunication device, in particular a radio device, with a switching arrangement constructed as a ring circuit and comprising four switching paths each with a switching element, which switching arrangement serves to couple two first signal paths to two second signal paths, as required, while its switching elements are connected in parallel to compensation branches which each serve to generate a parallel resonance in conjunction with a non-conducting switching element.
A radio device is known from DE 44 30 987 C1 which comprises a switching arrangement arranged as a ring circuit with four switching paths. The switching paths each comprise a switching element and serve to couple the transmitter or the receiver of the radio device to one of two transmission or reception antennas. If, for example, the transmitter of the radio device is coupled to one of the two antennas for radiating a signal, the coupling of the signal generated by the transmitter via the switching arrangement to the receiver is to be suppressed, i.e. a switching element of the switching arrangement, when in the non-conducting state, must not allow in particular high-frequency signals to pass, or no more than insubstantial portions thereof.
It is furthermore known to connect a compensation branch in parallel to each switching element, which branch generates a parallel resonance together with the parallel switching element in the non-conducting state thereof, provided the switching elements are constructed as semiconductor switches. This enhances the blocking action of a semiconductor switch in the open (non-conducting) state. The blocking action of an open semiconductor switch is adversely affected by the fact that, in the non-conducting state, a capacitance is active with respect to the exterior which is essentially determined by housing influences, leading to a reduced damping, or a partial passage of high-frequency signals. This is relevant to all radio applications, for example in GSM devices ("Global System for Mobile communications") or DECT devices ("Digital European Cordless Telecommunication"). The compensation branches connected in parallel serve to compensate for this effect.